"We never know the worth of water till the well is dry." ~Thomas Fuller, Gnomologia, 1732
According to the EPA, 70% of the pollution in our surface water is the result of stormwater contamination. The truly alarming part of that statistic is that 50% of that contamination comes from small businesses and individual homeowners. Yikes! Considering that fresh, drinkable water is a rare and becoming rarer commodity, the idea that 50% of that remaining supply is undrinkable (without treatment) because of its passage through peopled places is criminal. We all need it--clean water is simply not optional.
What causes the contamination? Automobiles, lawn care products, household chemicals...any number of things we use to "improve" our lives. Realistically, some of those improvements are really just for appearance. Some feel more like a necessary evil, like transportation. The question is, since individual homeowners contribute to the problem, is there anything a responsible, individual homeowner can do to improve the water supply?
"It is a curious situation that the sea, from which life first arose, should now be threatened by the activities of one form of that life." ~Rachel Carson
Remediation can be accomplished in a number of ways on the homeowner level. First, use pesticides and other chemicals sparingly if at all. The same with chemical fertilizers that are typically derived from petroleum. Natural fertilizers like bone and blood meal are more easily utilized by plants anyway, since they don't have the impact of, say, a Red Bull. These are remediations of omission -- things we should avoid if possible.
One of the advantages of establishing a rain garden is that you get to create a new microclimate for plants that like to get their feet wet on occasion. These can include trees, shrubs, perennials--some of my favorites are also favored by hummingbirds. A truly terrific site that includes design templates is online courtesy of the Low Impact Development Center. Check the PDF at the bottom of the linked page on "Rain Catching Garden."
One aesthetic consideration not really shown on any of the linked sites is the "buried piped" method of collecting water from a downspout. You really don't have to live with a downspout extension that travels 20 feet across your yard to a rain garden. Dig a shallow trench, lay a 4" solid corrugated pipe--connected to your downspout(s)--recover the pipe. Oh. The trench should lead to your rain garden.
After your first rain garden, you're probably going to be so thrilled that you want to convert everybody. If you raise enough community interest, you can do larger projects for schools and other hugely-paved institutions. For some discussion on how to tackle a project like that, check out the W.A.T.E.R. site.
Natives are the best plants for rain gardens. Here in our little shared corner of the planet, we are using lobelia cardinalis, tradescantia, asclepias incarnata, iris virginica, and chelone glabra for flowers. Each will do their best to beautify your personal stormwater detoxification zone and bring you butterflies and hummingbirds to boot. And you will have helped put clean water back on the planet.
Surface water contamination is a problem first of movement. It becomes a moving force during storms, building volume beyond what can be absorbed by suburban lawns and paved surfaces, tumbling into our streams and rivers and eventually to the ocean. Dead zones like the one in the Gulf of Mexico are the result of too many of these contaminants. Because this contaminated water travels through so many zip codes it can have impacts far beyond its original source. This means that pesticides used in Brevard, NC (for example), can end up impacting bees in Knoxville, TN (by way of the French Broad River).
What else? If you're the renovating type, you can replace a hard-surface drive with a permeable surface drive like permeable concrete pavers. The most fun remediation, however, is a remediation of addition--a rain garden.
Rain gardens are not wetlands. They are not designed to stay wet. They are designed strictly to slow the flow of storm water and increase infiltration of storm water into the soil. The easiest rain gardens are installed in sandy or silty soils. Even clay soils can support rain gardens, however--they just take a little more work and planning. Plan on tilling in some (about 4 inches) finely-ground hardwood mulch before planting. For a fairly quick summary of rain garden creation in clay soil, check here.
The activist is not the man who says the river is dirty. The activist is the man who cleans up the river. ~Ross Perot